Adjustable-beam luminaires with automatic beam controller

ABSTRACT

A luminaire for providing configurable static lighting or dynamically-adjustable lighting. The luminaire uses an array of focusing elements that act on light provided via a corresponding array of sources or via an edge-lit lightguide. Designs are provided for adjusting the number of distinct beams produced by the luminaire, as well as the angular width, angular profile, and pointing angle of the beams. Designs are also provided for systems utilizing the adjustable luminaires in various applications.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. application Ser.No. 17/065,357 filed on Oct. 7, 2020 (the entire contents of which arehereby incorporated by reference), which is a continuation of U.S.application Ser. No. 16/353,647, filed on Mar. 14, 2019, which is acontinuation of U.S. application Ser. No. 15/715,017, filed on Sep. 25,2017, which claimed priority to the following US provisionalapplications, which are incorporated herein by reference: Ser. No.62/399,911, filed Sep. 26, 2016, by Christopher Gladden et al.; Ser. No.62/452,381, filed Jan. 31, 2017, by Barbara Kruse et al.; Ser. No.62/457,819, filed Feb. 11, 2017, by Peter Kozodoy.

GOVERNMENT LICENSE RIGHTS

This invention was made with Government support under contractDE-AR0000332 awarded by the Advanced Research Projects Agency-Energy(ARPA-E), a division of the Department of Energy. The Government hascertain rights in the invention.

FIELD OF THE INVENTION

The present invention relates to optics, specifically to optical systemsfor controlling beam properties in illumination.

BACKGROUND

Directional lighting is important in many contexts, for example inproviding illumination for task areas in a workplace, for highlightingobjects in a retail space or an artistic exhibition, for illuminatingwalkways and roadways outdoors, and many more applications.Commonly-used light fixtures that provide the option to adjust lightingdirectionality typically include an illumination “head” that can beswiveled to point in a desired direction. Multiple heads are oftenincluded in a single light bank or in a configurable system such as atrack lighting system. Adjustments to the angular spread of the outputbeam from each head is typically achieved by installing a bulb with thedesired output beam width.

A planar adjustable luminaire design of prior art is disclosed in JosephFord PCT/US2014/057873 “Microstructured Waveguide Illuminator” andWilliam M. Mellette, Glenn M. Schuster, and Joseph E. Ford, “Planarwaveguide LED illuminator with controlled directionality anddivergence,” Optics Express vol. 22 No. S3, 2014 (Mellette et al). Thisdesign offers the potential advantage of a compact low-profile formfactor with wide adjustability. The luminaire uses an edge-illuminatedlightguide with periodic extraction features that is mated to an arrayof refractive lenses or reflectors (“focusing elements”). By adjustingthe relative location of the extraction features and the focusingelements, the direction of the beam can be steered and the angular widthof the output beam can be adjusted. FIG. 1 provides an exploded view ofsuch a design. It includes a lightguide 10 that is illuminated by alight source 11, in this example composed of light emitting diodes(LEDs) 20 and associated coupler optics 18. The lightguide 10 may be ofa continuous-mode type as shown in FIG. 1 or a stepped-mode type. Ineither case, the lightguide includes a periodic array of extractionfeatures 12. These features reflect or scatter light so that it is nolonger trapped in guided modes of the lightguide and instead exits thelightguide to interact with the array of focusing refractive lenses 24.The extraction features shown in FIG. 1 are reflective and arepreferably shaped as prisms to deflect guided light toward the focusingelements, but may also be shaped as cones, hemispheres, or other shapes.They lie approximately in the focal plane of the focusing elements sothat light scattered by the extraction elements is substantiallycollimated by the focusing elements. The refractive lens array 24 iscomposed of individual refractive lenses 25 all in a single plane. Thelenses 25 substantially collimate the light before it exits theluminaire into the environment.

FIG. 2 is a cross-section view of a portion of an adjustable luminaireof prior art that uses reflective focusing elements. The array ofreflectors 14 is composed of dielectric-filled reflective lenses 15 withreflective coating 19. One extraction feature 12 is associated with eachreflective lens. Light from the light source 11 is guided in thelightguide 10. Some of the light is deflected by extraction features 12to exit the guide 10 and enter the reflector array 14. These light rays13 reflect off the reflective coating 19 becoming partially collimated,and then transit through the lightguide 10 before exiting the luminaireas output light beam 16. Note that light rays emanating from the lightsource 11 and traveling within the guide 10 are not depicted in FIG. 2in the interest of visual clarity; only example light rays 13 deflectedby one of the extraction elements 12 are shown.

FIG. 3 is a ray trace diagram showing an example four-lens refractivefocusing element array in the luminaire of prior art. The figuredemonstrates control over the characteristics of the output beam of theluminaire. Each individual lens 25 serves to substantially collimate thelight reflected or scattered by the corresponding extraction feature 12so that it is emitted into the environment as a directional beam 16 ofnarrow angular width. Control over the directionality of the individualbeams 16 is achieved by varying the relative location of the extractionfeature 12 and the lens 25. This can be achieved by translating thearray of lenses 24 relative to the extraction features 12 in thelightguide. As the location of the extraction feature 12 moves from thecenter of the lens 25 (as in FIG. 3a ) to the edge (as in FIG. 3b ), theoutput beam 16 is steered from perpendicular to the plane of thelightguide to a high angle.

If all lenses in the array 24 are identical in optical formula and bearthe same orientation relative to their corresponding extraction features12, then all the output beams 16 will point in the same direction. Inthat case, all the focusing elements are contributing to a narrowaggregate beam pointed in a single direction. Alternatively, if thelenses in the array 24 are twisted relative to the array of extractionfeatures 12, as shown in FIG. 3c , then each of the output beams 16 willpoint in a somewhat different direction. In that case, the aggregateoutput beam 17 is the sum of the differently-pointed beams and resultsin a wider aggregate beam. Therefore, independent control over beampointing and aggregate beam width is provided by translating andtwisting the relative position of the focusing element array and theextraction element array. The same mechanism applies in the case of bothrefractive and reflective focusing elements.

The prior art describes several implementations of this design,including the use of motorized actuators and a control system to provideremote control over the output characteristics of the adjustableluminaire. The prior art also describes the use of a switchable materialin the lightguide that provides for pixelated control over the locationand presence of the extraction features. The prior art describes amechanism for controlling this whereby a layer of liquid crystalmaterial with electrically-adjustable refractive index is placed on theface of the lightguide. In its low-refractive-index state, this materialacts as cladding to keep light confined within the lightguide. Pixelatedelectrodes allow it to be locally switched to a high-refractive-indexstate, allowing light to locally interact with a tilted mirror array andbe ejected from the guide. This provides a mechanism for local controlover the location of the extraction feature. The design can beimplemented with a stationary lens array to provide a steerableluminaire design with no moving parts.

Mellette et al also discusses using an array of point-like LED sourcesin place of the lightguide, but teaches that the idea is impractical inits various embodiments. The idea is described as having a thicker formfactor than a system comprising a lightguide, categorically not allowingfor the use of reflective lenses, and incapable of matching theefficiency and total brightness of a system comprising a lightguide.Mellette et al specify the use of the Cree XM-L2 LED, which is a largeLED with a tall integrated silicone dome and their drawings depict domedLEDs.

While the prior art described above provides for major advantagescompared to conventional steerable luminaires, it still suffers fromvarious limitations affecting implementation for specific applications.These include (i) beam widths that are wider than is desirable for someapplications, (ii) provision of only a single adjustable beam output perluminaire, (iii) restriction to a square or nearly-square form factor inorder to maintain a full range of beam width control via twisting, and(iv) performs with extremely low efficiency.

SUMMARY OF THE INVENTION

This filing describes a number of inventions for the realization andoptimization of adjustable luminaires.

In accordance with a preferred embodiment, a luminaire is described inwhich the direction, shape, and spread of the emitted light can beadjusted or configured.

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides an exploded view of an adjustable luminaire of priorart.

FIG. 2 provides a cross-section view of a section of an adjustableluminaire of prior art.

FIG. 3 (a) provides a ray trace of a section of an adjustable luminaireof prior art with extraction features centered under the focusingelements and ray trace depiction of output light beams; FIG. 3(b)provides a view in which the extraction elements are translated to theedge of the focusing elements; FIG. 3(c) provides a view in which thearray of extraction elements is twisted in relation to the array offocusing elements.

FIG. 4 provides a cross-section view of a section of an adjustableluminaire with downconversion materials located at the extractionfeatures.

FIG. 5 provides a perspective view of an adjustable luminaire withdirect light source illumination.

FIG. 6 provides a cross-section view of a section of an adjustableluminaire having multiple extraction features associated with eachfocusing element.

FIG. 7a and FIG. 7b provide two orthogonal cross-section views of anadjustable luminaire having elongated extraction features and producinga beam that is wider in one axis than another.

FIG. 8a provides a cross-section view of a luminaire having extractionfeatures and focusing elements that do not all share the sameperiodicity and that produces an asymmetric output beam; FIG. 8bprovides an example asymmetric beam intensity profile.

FIG. 9 provides a cross-section view of an extended luminaire havingextraction features and focusing elements that do not all share the sameperiodicity and that produces converging output beams.

FIG. 10 provides a cross-section view of a section of an adjustableluminaire with catadioptric focusing elements.

FIG. 11 provides a cross-section view of a section of an adjustableluminaire with z-axis adjustment of output beam width.

FIG. 12 provides a cross-section view of a section of an adjustableluminaire with partially transmissive reflector coating.

FIG. 13 provides a cross-section view of an adjustable luminaire withmultiple independently-controllable output beams.

FIG. 14a provides a perspective view of a modular adjustable luminairewith multiple attachment locations; FIG. 14b provides a cross-sectionview of an attachment for providing steerable directional lighting; FIG.14c provides a cross-section view of an attachment for providing broaddownlighting; FIG. 14d provides a cross-section view of an attachmentfor providing broad uplighting.

FIG. 15 provides a cross-section view of a modular adjustable luminairewith variable attachment locations.

FIG. 16 provides a top-view of an adjustable luminaire with cam-drivenadjustment of output beam steering and spread.

FIG. 17 provides a cross-section view of an adjustable luminaire withglare-reduction pivoting louvers.

FIG. 18 provides a cross-section view of an adjustable luminaire with aprotective cover layer adjacent to the light guide.

FIG. 19 provides a perspective view of an adjustable luminaire withmultiple types of active elements coupled to the light guide.

FIG. 20 provides a schematic view of an adjustable illumination systemincluding an adjustable luminaire as well as optional manual andautomated control systems and sensor inputs.

FIG. 21 provides a view of an adjustable luminaire mounted into thepanel of a car.

FIG. 22 provides a view of an adjustable luminaire mounted in theunderside of the wing of an aerial vehicle.

FIG. 23A shows a waveguide with a first orientation of athree-dimensional extraction feature.

FIG. 23B shows a waveguide with a second orientation of thethree-dimensional extraction feature, angled 90 degrees from the firstorientation.

FIG. 24A shows a waveguide with a half-toned, two-dimensional extractionfeature.

FIG. 24B shows a waveguide with a filled, two-dimensional extractionfeature.

FIG. 25 shows an array of 50% filled extraction features, dithered tocreate a single uniform beam, similar to the output of a fully filledcircular extraction feature, with 50% less energy.

FIG. 26 provides a cross-section view of a configurable lightfieldluminaire. Light rays from the light source are omitted for clarity.

FIG. 27 provides a perspective view of a configurable lightfieldluminaire. The light source is omitted for clarity.

FIG. 28A is an example of a projected custom lightfield using an arrayof coupling features, where each hexagon corresponds to a single lens.

FIG. 28B illustrates the light output of the structure of FIG. 28Aplotted in angle space.

FIG. 29 provides a cross-section view of a lightfield luminaire usingrefractive optics.

FIG. 30 provides a cross-section view of a lightfield luminaire usingcatadioptric optics.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

Part 1: Light Sources

1a: Edge-Lit with Remote Downconversion Materials

A variety of light sources may be used in the edge-lit luminaire device.Among other sources, these include light-emitting diode (LED) and laserdiode (LD) sources. These light sources are attractive as they are smalland can operate at high optical efficiency. In order to providefull-spectrum white light, these sources are often utilized with one ormore downconversion materials such as phosphors that convert a portionof the light to lower-energy longer-wavelength light. In some devices,the downconversion medium is placed directly on the LED or LD device toform a white-light-emitting component. Placing the downconversionmaterials away from the LED source improves efficiency by reducing theamount of light scattered back into the LED source. Also, somedownconversion materials do not operate well at the elevatedtemperatures present at the LED or LD device, and instead are bestutilized at a remote distance from the devices. In any optical systemwhere light traverses the system multiple times, such as in an edge-litluminaire, or where phosphor-coated light sources are placed near eachother, such as in a closely spaced array of light sources, blue lightemitted by the light sources encounters downconversion materials severaltimes and the average color of the light shifts towards the color of thedownconversion material emission and away from the desirable Planckianblack body locus of color; this becomes a practical problem because thecolor shift depends highly on the design of a given system and lightsources of the necessary color to counteract the color shift are notreadily and economically available.

An improved luminaire design is shown in FIG. 4. It has downconversionmaterials 5 present at the extraction locations, replacing or augmentingthe use of downconversion materials in the light source 11. Thisimplementation of the downconversion material remote from the source 11permits the use of higher performance downconversion materials thanotherwise possible. The downconversion material at the extractionlocation absorbs some of the light incident upon it, and then emitslight at a lower energy. It may also act to scatter or reflect some ofthe incident light without absorption. The downconversion material isoptimized so that the combined scattered and downconverted lightachieves a desired output spectrum. It may be a mix of differentcompounds designed to tailor this spectrum. In addition, thedownconversion material may be shaped into a shape such as a cone or aprism in order to optimize the capture and directional scatter andre-emission properties within the guide. Finally, the downconversionmaterial may be implemented as a coating applied to a specular orscattering extraction feature like those of prior art.

1b: Direct-Lit

FIG. 5 depicts a luminaire design that includes an array of lightsources 30, each coupled to a reflective lens 15. The light sources 30may be of any type but are preferably LEDs or LDs for compactness andefficiency. Vertical-cavity surface-emitting laser diodes (VCSELs) areanother option for the light source. In all cases, the light sources areconnected in a network electrically and by heat spreading elements. Theelectrical connections bring electrical power to the light sources todrive them, and the heat spreading elements are used to route heat awayfrom the sources to reduce operating temperature. The electricalconnections and heat spreading elements may be optionally combined intoa single structure or even combined into a single element. This is shownin the example system of FIG. 5, where a strip of metal-core printedcircuit board (MCPCB) 32 connects individual light sources 30 in a line,providing both electrical connections and a heat spreading element.

It is advantageous to design the system so that the emitting area of thelight source 30 is much smaller than the area of the reflective lens 15,enabling the focusing element to produce a beam of a narrow angularwidth. For example, the diameter of the focusing element may beapproximately 5 to 20 times the diameter of the light emitting area ofthe source. The light emitting area and the thickness of the lightsource 30 can also be significantly minimized by selecting light source30 that do not have any significant encapsulating clear dome; forexample, a small and flat non-domed LED or chip-scale packaged LED, asillustrated as the light source 30 in FIG. 5.

This design may be implemented with either refractive or reflectivefocusing elements. When implemented with a reflector array 14, as shown,it is also advantageous to minimize the area of the electricalconnections and heat-spreading elements, as these will shadow thereflected light and reduce system optical efficiency. In one preferredembodiment, the luminaire comprises MCPCB 32 and small and flat LEDs asthe light source 30 to minimize shadowing, as shown in FIG. 5.

The direct-lit design uses the arrayed light sources 30 in place of thelightguide and extraction features used in the edge-lit designs. Itshares the same adjustable functionality, however. Aggregate beamsteering is achieved by translating the array of focusing elementsrelative to the array of light sources, and aggregate beam broadeningcan be achieved by twisting the array of focusing elements relative tothe array of light sources.

An advantage of the direct-lit design is that it can be implemented withhigh optical efficiency in a small form factor. The edge-lit design canrequire an array of a certain length in order to achieve a targetoptical efficiency, because of the requirement to extract light from alightguide. Also, the edge-lit design requires a certain thickness oflightguide 10 to maintain a flat shape when fabricated of plasticmaterials, to have sufficient mechanical toughness against breakage whenfabricated of any transparent materials, and to provide for sufficientin-coupling of light from light source 11; for example, this thicknesscan be 1.5 mm to 5 mm and the required thickness increases as the sizeof the lightguide 10 increases. In contrast, the direct-lit design canbe produced with any number of light sources in an array, including evenonly a single light source. The direct-lit design can also be producedas thin or thinner than an equivalent edge-lit design, where small andflat LEDs typically under 0.7 mm in thickness are used as light source30 with MCPCB 32 typically 1.0 to 2.0 mm in thickness, while havingsuperior flatness and resistance to breakage over an edge-lit design.

The remainder of this filing provides further improvements to theoptical and system design of adjustable directional luminaires. Theseare generally described in implementations that use the light-guidedesign, however it should be understood that in most cases they can beequivalently realized using a direct-lit design.

1c: Geometry

The prior art considers only a single array of extraction featuresassociated with the array of focusing elements. An improved inventionallows for multiple arrays of extraction features in a single lightguideand associated with a single array of focusing elements. These multiplearrays of extraction features may all feature the same periodicity asthe focusing element array, so that each focusing element is associatedwith multiple extraction features and therefore outputs multiple outputbeams at multiple different steering angles. Translation of the focusingelement array relative to the lightguide thereby steers all the multipledifferent output beams simultaneously. FIG. 6 shows a system with twoextraction features 12 associated with each reflective lens 15. Thesetwo features produce two distinct output beams, 3 and 4. This inventionmay also be realized in a direct-lit luminaire by placing multiple lightemitters within the focal plane of each focusing element.

The prior art considers only extraction features that are ofapproximately unity aspect ratio in the plane of the light guide, suchas a prism that occupies a square area in the plane of the light guide.An improved invention allows for the use of extraction features that areelongated in one axis. This produces an output beam that is asymmetric,having a broad beam spread in one axis and a narrow beam spread in theperpendicular axis. This is shown in FIGS. 7a and 7b , which depict aluminaire in two orthogonal cross-section views. The extraction features21 are narrower in the cross section of FIG. 7a and wider in thecross-section of FIG. 7b , being elongated in that axis. This producesan output beam 16 that is narrow in one axis (as shown in FIG. 7a ) andwide in the second axis (as shown in FIG. 7b ). The elongation mayoptionally be extended to the entire width of the focusing element. Thisinvention may also be realized in a direct-lit luminaire by utilizingelongated light sources or multiple light sources arrayed in anelongated pattern.

The prior art considers only regular arrays of extraction features andfocusing elements, all of equal size and sharing precisely the sameperiodicity. An improved invention allows for the use of extractionfeatures and focusing elements of varying periodicity and size in orderto create a desired beam profile.

For example, a ceiling-mounted luminaire of prior art will produce asymmetric beam that results in an elongated projected spot of unevenbrightness when projected onto a vertical wall. An improved luminairedesigned for such an application can counteract this by tailoring thesize and relative position of the extraction features and focusingelements within the array to produce an asymmetric beam. Each extractionfeature produces an output beam, and the aggregate output beam is thesum of these individual beams. The arrays may be designed withnon-matching periodicity, so that beams of different pointing angles areproduced by different focusing elements. The intensity of the aggregatebeam across these different beam angles may be tailored by adjusting thenumber of focusing elements outputting at each angle in order to providethe desired asymmetric beam profile. The asymmetric beam may be steeredand broadened using the same mechanisms described above.

An example luminaire is shown in FIG. 8a . Extraction features 150 sharethe periodicity of the reflector array 14 and are centered with respectto their associated focusing elements, while extraction features 151 donot share the periodicity of the focusing element array and are spreadso that each extraction feature 151 is differently aligned to itsassociated focusing element, in this case ranging from centered tooffset at one edge. The resulting output beam profile 152, as shown inFIG. 8b , has a central lobe formed primarily by the extraction features150 and is extended asymmetrically in one direction as a result of theextraction features 151.

Another use of this invention is to provide beam pointing that varies ina deterministic way with position in the focusing element array. Forexample, a luminaire that provides a steerable spotlight in a linearform factor with a high aspect ratio may be desired. Such a luminairecould have an example length of between 12 and 36 inches. In order toprovide a small spotlight from such an extended source, it may bedesirable to have the beams point in different directions along thelength of the array, so that they tend to converge toward a spot at atypical use distance from the luminaire. This can be achieved, forexample, by designing the spacing of the extraction feature array to beslightly larger than that of a reflective focusing element array alongthe length of the luminaire. This is shown in FIG. 9, which depicts aluminaire in which the periodicity of the extraction features 12 isslightly larger than that of the reflector array 14. As a result, thebeams 160 and 164 from the ends of the array tend to converge toward thecenter, combining with beam 162 to form a narrow spot at a desireddistance from the luminaire.

Note that these inventions may also be realized in a direct-litembodiment by varying the size and periodicity of the light source arrayand focusing element array.

Part 2: Focusing Elements

2a: Catadioptric Optics

The prior art steerable luminaire describes the use of single refractivelens array (as in FIG. 3) or reflector array (as in FIG. 2). FIG. 10describes a new option: the use of catadioptric optics that combine botha reflector array 50 and a refractive lens array 51. One reflector andone refractive lens are associated with each extraction element 12 (orwith each light source if used in a direct-lit configuration, notshown). The extraction features 12 sit at the approximate focal plane ofthe combined focusing elements made of the reflector and refractive lensarrays. The reflector array 50 and refractive lens array 51 are kept inpermanent alignment to one another, and move relative to the lightguideextraction features 12 in order to provide beam steering and beambroadening. Combining reflective and refractive elements permits a morenarrow output beam to be maintained over a wider range of output anglesthan can be achieved with only a single type of focusing element. Thisis because the combined catadioptric system maintains a more flat focalfield than can be achieved with a single focusing device. While FIG. 10describes an edge-lit embodiment of this invention, it can also berealized in a direct-lit configuration by utilizing an array of lightsources rather than an array of extraction features in an edge-litlightguide.

2b: Focusing Element Design

The prior art designs envisioned focusing elements that are rotationallysymmetric, therefore providing a symmetric output beam. An additionaloption is to use focusing elements that have toroidal surfacescharacterized by a different radius of curvature and different asphericterms in the two primary axes. This results in oval-shaped output beams,which can be advantageous in various situations. In an extreme case ofthis design, the focusing elements may be made cylindrical so that theyprovide focusing in one axis only, leaving the other axis unfocused.Examples of applications that can benefit from oval-shaped output beamsinclude lighting of linear spaces such as hallways, and lighting ofvertical surfaces (such as wall-mounted art), where an oval beam shapecan be used to counter the tendency of a symmetric beam to becomestretched when projected onto the vertical surface.

Part 3: Beam Control

3a: z-Axis Beam Spread Control

The prior art described the use of twisting actuation to vary theangular divergence of the aggregate output beam. We describe here analternative mechanism to control output beam divergence. FIG. 11 shows asystem using a reflector array 14 and an edge-lit lightguide 10 withextraction features 12. The gap 60 between the reflector array 14 andthe lightguide 10 may be dynamically varied. Doing so causes theextraction features 12 to move in and out of the focus of the reflectorelements in 14, causing the output beam 16 to narrow and widen. Thus,beam width modulation is provided by translating the reflector array 14relative to the lightguide 10 in the direction perpendicular to thelightguide 10 (the “z-axis”). Further, this translational control ofbeam width may be combined with in-plane twisting actuation if desired.While FIG. 11 describes an edge-lit embodiment of this invention, it canalso be realized in a direct-lit configuration by utilizing an array oflight sources rather than an array of extraction features in an edge-litlightguide.

3b: Combined Directional and Omnidirectional Lighting

It may be desired to combine adjustable narrow-beam directional lightwith an amount of broad-angle general lighting. Various mechanisms arepresented here for achieving this end.

One mechanism is to introduce scattering elements randomly distributedin the lightguide so that a fraction of the guided light is scatteredout and forms a broad-angle aggregate beam. The scattering elements mayalso be placed in the focusing element array if desired.

Another mechanism is shown in FIG. 12. This design uses a reflectorarray 14 with a reflective coating 70 that is partially transparent andpartially reflective. In this system, the portion of the light that istransmitted through the reflective coating 70 exits in a broad upwardbeam 71 forming a broad-beam uplight, while the portion of the beam thatis reflected forms an adjustable directional downlight beam 16. WhileFIG. 12 describes an edge-lit embodiment of this invention, it can alsobe realized in a direct-lit configuration by utilizing an array of lightsources rather than an array of extraction features in an edge-litlightguide.

Part 4: Multiple Segment Design

The prior art contemplated luminaires with a single adjustable aggregateoutput beam. FIG. 13 depicts a new system design, which can includemultiple independently-adjustable reflector arrays 14. The reflectorarrays are utilized with a rectangular lightguide 10 that has extractionfeatures 12 in multiple arrays corresponding to each of the reflectorarrays 14. The light guide is edge-lit by light sources 11 that may bepresent on one or more sides of the lightguide, with the unlit sidesoptionally coated by a reflective material to increase opticalefficiency. Each of the reflector arrays 14 produces a separateaggregate output beam that can be independently pointed and adjusted viain-plane translation and twist, and/or z-axis translation. The system isunique and novel in providing a number of independently-adjustabledirectional lights from a common light source and a single fixture. Foran edge-lit system, the longer optical path length that may be used withmultiple independent arrays increases the light extraction efficiency ofthe system.

We note that, if desired, similar systems featuring multipleindependently-adjustable output beams can be achieved using refractivelens arrays instead of reflector arrays, and/or utilizing a direct-litgeometry in place of the edge-lit system shown in FIG. 13.

FIG. 14a depicts a modular system in which a lightguide 10 is providedwith multiple arrays of extraction features 12, each such arrayproviding an attachment location 100 for a modular output device. Eachsuch location 100 can be utilized to form a directional beam or a broadarea beam by the choice of attachment placed adjacent to the lightguide. The attachments are shown in FIGS. 14b, 14c, and 14d . They maybe attached adjacent to the light guide by any number of means. Oneexample attachment mechanism is the use of magnetic attraction to holdthe attachments in place, while still permitting them to be translatedand twisted for output beam control. This magnetic attachment schemeuses magnetic materials 111 and 112 embedded in the frame 110 around thelightguide 10 and in the attachment parts respectively. At least one ofthe magnetic materials 111 and 112 is a permanent magnet, while theother may be a ferromagnetic material. The mounting of the attachmentsmaintains a gap between the lightguide and the attachment. This gap maybe filled with air or another low-refractive-index material to serve ascladding for the light guide.

If the reflector array 14 shown in FIG. 14b is placed adjacent to thelight guide in location 100, it will provide an adjustable directionallight output as described earlier. The attachment can be positioned bysliding the attachment against the magnetic material 111 in the frame,allowing the reflector array 14 to be translated and twisted relative tothe extraction features 12.

FIG. 14c shows another attachment option: a broad-area reflector 101.This reflector is formed by an optional transparent layer 102 and areflective layer 103. The reflective layer 103 may be specularlyreflective or scattering in nature. In either case, placement of thebroad-area reflector 101 in the attachment location 100 results in abroad downward beam output.

FIG. 14d shows another attachment option: an uplight attachment 104. Theuplight attachment consists of an optional transparent layer 105 and anoptional diffusive layer 106 that diffuses light. Placement of theuplight attachment 104 in the attachment location 100 results in abroad-beam uplight output. Such output can also be achieved by leavingthe attachment location 100 without an attachment.

Another option (not shown) is an attachment providing a combination ofuplight and downlight by utilizing a partially transmissive andpartially reflecting coating.

The designs provided here result in a configurable luminaire that canprovide multiple adjustable directional beams as well as broad-beamuplight and downlight. The segments can be reconfigured by the user toprovide whatever combination of these three is desired, and to readjustthe combination over time as desired. While FIG. 14 describes anedge-lit embodiment of this invention, it can also be realized in adirect-lit configuration by utilizing an array of light sources ratherthan an array of extraction features in an edge-lit lightguide.

A further modification to this system design is shown in FIG. 15. Inthis case, the lightguide 10 is provided without extraction features.The arrays of extraction features 12 are instead prepared in a separateextraction array material 120. Each extraction array material 120consists of a transparent layer of rigid or flexible material with asingle array of extraction features 12 embedded within it. Theextraction array material 120 can be placed on the lightguide 10wherever is desired in order to produce an attachment location 100 forlight output. In each such location, a reflector array 14 may be placed(as shown), or other attachments may be used. Multiple extraction arraymaterials 120 can be utilized with a single long lightguide, allowingdirectional output beams to be placed wherever desired along a track. Inorder to ensure effective light extraction, the extraction arraymaterials 120 must be mated to the lightguide 10 with no air gap, sothat light transits from the lightguide 10 into the extraction arraymaterial 120. To facilitate this, the extraction array materials mayincorporate a transparent adhesive layer, or may be made of materialsthat “cling” effectively to the lightguide 10.

Part 5: Actuation

Adjustment of the beam properties is achieved by altering the relativeplacement and orientation of the focusing element array and thelightguide, with its array of extraction features. Many mechanicalconfigurations are possible for manual or motorized adjustment of therelative location for these two pieces. The magnetic mounting schemeshown in FIG. 14 is one such system. The focusing element array may bemoved relative to the light guide by hand, either by sliding it directlyor with any sort of handle attachments. For example, a handle attachmentprotruding from the focusing element array could be combined with apivot to provide a joystick-type actuation mechanism.

FIG. 16 shows a top view of another mechanical configuration permittingadjustment of the relative orientation of the lightguide and thefocusing element array. A reflector array 14 is in contact with threecams (121, 122, and 123) mounted to stationary frame 126. The reflectorarray is held against the cams by leaf springs 124. One side of thereflector array is in contact with a single cam 121. The rotationalposition of this cam controls translation of the array in one axis(labeled here as the “x” axis). A perpendicular side of the array is incontact with two cams 122 and 123. The “y” axis translation of the lensarray is controlled by adjusting cams 122 and 123 together and is set bytheir average extension, while twist rotation of the lens array iscontrolled by adjusting cams 122 and 123 separately and is set by thedifference between the extension of these two cams. The cams may beconnected to knobs for manual control over beam direction and width, orconnected to motors for automated control. FIG. 16 depicts the cams andleaf springs in contact with the edges of the reflector array, but theycould also act on the reflector array from other locations, for exampleon small protrusions attached to the center of the reflector array. Sucha design would provide a more compact luminaire form factor by allowingthe cams and leaf springs to fit within the perimeter of the reflectorarray and/or light guide. Further, the leaf springs may be replaced withother mechanisms for providing restoring force, such as wound springs,compressible materials, etc. Further, we note that while FIG. 16describes an edge-lit embodiment of this invention, it can also berealized in a direct-lit configuration by utilizing an array of lightsources rather than an array of extraction features in an edge-litlightguide.

Beam Pointing and Glare Control

The luminaire may be configured to allow beam pointing in only one axis,or in two axes by appropriately constraining translation of the focusingelement array relative to the lightguide or light source array. Further,the entire luminaire may be mounted in a frame to swivel in one or twoaxes, to provide additional mechanisms of beam pointing. For example, aluminaire with a rectangular form factor could be designed to swivel ina frame about its long axis and to provide beam pointing in the otheraxis via translation of the focusing element array relative to thelightguide or light source array.

An advantage of the inventions described herein is that the luminairesprovide highly directional light with minimal glare outside of thedirectional beam. Nonetheless, it may be desired to shade the luminaireoutput to further reduce glare. FIG. 17 provides an example of a systemwith integrated louvers to provide such glare reduction. The louvers 130are made of an opaque material and attached to a frame element 110 andthe reflector array with pivoting connectors 131. As the reflector array14 is translated to steer the beam, the louvers 130 automatically tiltto block light outside the steered beam. While FIG. 17 describes anedge-lit embodiment of this invention, it can also be realized in adirect-lit configuration by utilizing an array of light sources ratherthan an array of extraction features in an edge-lit lightguide.

An additional invention to reduce glare and improve luminaireperformance is shown in FIG. 18. A cover layer 190 is placed adjacent tothe lightguide 10 on the side opposite the reflector array 14, andseparated from the lightguide by a gap 191 over the majority of the areaof the lightguide. The gap 191 may be filled with air and maintained bythe use of a frame that holds the cover layer 190 apart from thelightguide 10, by small spacers placed between the lightguide 10 and thecover layer 190, by the natural surface roughness of the cover layer, orby any combination of these or other schemes. Alternatively, the gap maybe filled by another low-refractive index material. The gap ispreferably large enough to ensure total internal reflection within thelightguide 10 so that very little of the light within guided modes ofthe lightguide 10 enters the cover layer 190. For visible-wavelengthlight, the gap is preferably greater than 2 microns. For a system withreflective focusing elements (as shown in FIG. 18), the cover layer 190is preferably made to be transparent. The function of cover layer 190 isto protect the lightguide 10 from the accumulation of dust, oil,fingerprints, and the like, which can scatter guided light and increasesystem glare.

Part 6: Additional Functionality

The inventions described above enable new functionality in steerabledirectional luminaires. They provide a capability for steerablespotlights with beam spread control that do not require external movingparts and provide a compact flat form factor. They enable multiple suchsteerable lights to be provided from a single luminaire and driven by acommon light source. They allow adjustable spotlights to be provided inluminaires with a linear form factor of high aspect ratio. They providefor asymmetric beam profiles that can be tailored for a variety of usecases.

Additional functionality can be added to the steerable luminaires inmany ways.

In a lightguide system, multiple types of active elements may be coupledto the edge of the lightguide. For example, FIG. 19 shows a system inwhich three types of active elements, 180, 181, and 183, are coupled tothe light guide. In one example, 180, 181, and 183 may be light sourcesof different spectrums—for example, LEDs of different colors or ofdifferent color temperatures. The different light source types may beconnected to separate drivers so that they can be controlledindependently. In this way, the output color or color temperature of thelight can be varied. Another example use of such a configuration is tohave one of the types of active elements be a colored light source thatcan be used as an indicator when adjusting the beam pointing of theluminaire, and the other active elements be white light sources used forillumination in normal luminaire use.

One or more of the active elements may also be a photosensor. Thesesensors measure light incident on the luminaire from differentdirections, with rays traveling back through the optical system to thesensors. Adjusting the direction or beam width of the luminaire therebyadjusts the direction and field of regard for the photosensors as well.This can have numerous uses. For example, with the light sources turnedoff, the system can be steered in a pattern to scan the area surroundingthe luminaire and measure brightness in each direction. The lightsources can then be turned on and beam direction and width set as neededin order to bring area illumination to a desired profile.

Another use of embedded photosensors is for optical communications.Infrared (or other wavelength) sensors and/or emitters can be integratedin the luminaire and used for directional optical communications.

While FIG. 19 describes an edge-lit embodiment of this invention, it canalso be realized in a direct-lit configuration by distributing thevarious active element types in the array of light sources rather thanplacing them on the edge of a light guide that contains an array ofextraction features.

Part 7: System Implementations

A wide range of system implementations are possible for the devicesdescribed above. FIG. 20 shows a general schematic of such a system. Asteerable luminaire 200 may be connected to a manual control system 220and an automated control system 210, which may itself be connected to asensing system 230. The manual control system allows for dynamic controlof illumination effects by an operator, and the automated control systemprovides for programmed variations in illumination effects and/ordynamic control of illumination effects in response to sensor inputs.Some specific design options are described below; we note that the listis far from exhaustive.

7a: Designs Optimized for Use on Moving Platforms

The adjustable illumination provided by this device is of great value onmoving platforms. In one embodiment, luminaires are mounted on theexterior of vehicles such as cars or boats. The luminaires may be usedas steerable spotlight/searchlights. Unlike conventional steerablespotlights that require a gimbaled motorized mount, these luminaires arethin and flat, enabling them to be mounted into the structure of thevehicle, such as in the door panel or front grill of a car or on theexterior of a boat. For example, FIG. 21 shows a steerable luminaire 200mounted in the door of a car 202. The system may further comprise a userinterface for controlling the direction and spread of the light beam(for example, a pointing joystick) and a microcontroller that controlsthe luminaire output.

In a second embodiment, steerable luminaire panels are mounted onairborne vehicles, such as on the underside of the wings of unmannedaerial vehicles. For example, FIG. 22 shows steerable luminaires 200mounted in the wings of an aerial vehicle 203. The luminaires so mountedmay be used to provide controllable illumination of the ground areabeneath the vehicle. Use of infrared light sources in such a system willprovide controllable infrared illumination of considerable value fornight-vision systems.

In a third embodiment, the luminaires may be implemented as an emergencylight and mounted on emergency vehicles. A controller can adjust theluminaire so that it provides a light beam that sweeps from side toside, drawing attention.

In a fourth embodiment, the steerable luminaire may be used tocounteract motion and stabilize the pointing of a beam that is emanatingfrom a moving platform such as a boat or truck. An active control systemwould include a sensor such as an accelerometer and a microcontrollerthat steers the luminaire to counteract movements of the platform onwhich the luminaire is mounted and keep the output beam targeted on afixed location. Alternatively, a passive inertial system may be used toprovide relative motion between the focusing element array and thelightguide, stabilizing the output beam.

7b: System Designs with Integrated Sensors

In one embodiment, the system performs as a voice-tracking spotlight. Asteerable luminaire is integrated in a system with a microcontroller andwith directional microphones as sensors. The signal from the directionalmicrophones is processed by the microntroller to determine the positionof a speaking individual and the microcontroller then aims the lightbeam at that individual. Such a system would provide automaticillumination of a speaker. It would be valuable as an automaticspotlight for theatrical use, and as an illumination tool fordiscussions in conference rooms and other gatherings.

In another embodiment, the system performs as a directional light thatautomatically tracks an individual. The system contains a steerableluminaire, a microcontroller, and one or more sensors used to determinethe location of an individual (these can include motion sensors, acamera feed linked to image processing software, acoustic sensors, orother sensor types). Such a system can be used in many implementations.In one implementation, it forms an automatic task light that follows anindividual as he or she performs tasks in various locations. This tasklight can reduce energy usage for lighting by selectively lighting thetask areas and reducing the need for high-brightness ambient lighting.In a second implementation, it forms an automatic intruder spotlight asa component of a security or alarm system.

7c: Systems for Daylight Integration

In one embodiment, the system performs to mimic daylight, providing anatural-feeling light source. A steerable luminaire is integrated in asystem with a microcontroller and is made to project a beam in achanging angle mimicking the sweep of directional sunlight. The systemmay further include spectral shifts over time to mimic the changingcolor temperature of sunlight over the course of the day and the year.

In a second embodiment, the system is made to augment natural sunlight(for example, from a window or skylight) as it sweeps across a space.The light beam from the luminaire is steered to provide “fill”illumination in areas that are insufficiently lit by the daylight beam.

In a third embodiment, the system is connected to a daylight harvestingdevice in order to emit daylight. This configuration requires alightguide-system wherein the lightguide is connected to a concentratingdaylight harvesting device so that the captured daylight serves as thelight source input into the luminaire. The luminaire may optionallyfeature additional electrically-powered light sources into theluminaire.

7d: Systems with Novel Control Schemes

In one embodiment, the system is provided with one or more remotelocator units featuring at least one button, switch, or other inputdevice. The luminaire is equipped with sensors to determine the relativelocation of the remote locator units, for example by radio signals. Theremote locator units provide a convenient lighting control system andmay be installed in multiple locations. For example, in a kitchen, suchremote locator units could be placed in commonly-accessed areas such asthe stove, food prep area, and eating areas. Users can direct light tothe area in which they are working by activating the input device on theremote locator unit in that location, and may optionally further controlthe beam with additional input devices on the unit. This system includesa microcontroller and a fixed sensor system to locate the position ofthe remote locator units (for example, this may be achieved via radiosignals), as well as the luminaire. In a variation of this system, theremote locator unit can be moved around to indicate the size of the areato be lit.

In a second embodiment, a luminaire control system is designed tocontrol multiple luminaires in a single room or space, adjusting thebeams from all luminaires to achieve desired aggregate lighting profilesin the room. The control system may optionally include a camera tomonitor total room lighting and adjust the luminaires as needed toprovide a desired lighting profile.

Part 8: Extraction Feature Optimization for Edge-Lit AdjustableLuminaires

8a: Non-Parallel Alignment of Extraction Surface Normal to PrimaryPropagation Path for Greater Beam Uniformity

FIG. 23 (a) shows a lightguide 310 lit by a light source 311, withextraction features 313 consisting of two 45° planes and two sideplanes. For this geometry, the two 45° planes are the primary extractionsurfaces. FIG. 23 (a) shows the alignment of the primary extractionsurfaces such that their normal vector has one component parallel to theprimary direction of light propagation within the lightguide and theother component in the desired extraction direction. FIG. 23 (b) showsextraction features 314, which have identical extraction geometry butthe normal surface rotated, such that one of the normal vectorcomponents is perpendicular to the primary propagation direction.

For a scattering reflective coating on the extraction surfaces, thegeometry in FIG. 23 (a) results in significant shadowing of the “back”surface—the side furthest from the source. With this geometry, the frontextraction feature sees significantly more energy, leading to adual-lobed beam output with one peak significantly higher than theother. With the rotated geometry depicted in FIG. 23 (b), the beamuniformity is significantly improved.

By rotating the extraction surface so that the surface normal isperpendicular to the light propagation direction, the shadowing effectis eliminated, but the high extraction efficiency of the volumetricscattered is maintained. This effect is due to the large amount ofre-scattered light present in the guide which intersects with theextraction surfaces uniformly no matter which direction it is travelingthrough the guide.

This invention is not limited to the extraction feature geometry shownin FIGS. 23 (a) and 23 (b). The requirement under this invention for anextraction feature to provide a uniform beam is that extraction surfacesthat contribute significantly to the beam are aligned so that thesurface normal vector is perpendicular to the primary propagation axiswithin the lightguide.

8b: Half-Toning and Dithering of Extraction Feature Fill for AdjustableExtraction Efficiencies

FIGS. 24A and 24B show an alternative construction of extractionfeatures. These are flat features formed by a reflective scatteringmaterial, such as white pigment, on one surface of the light guide. Suchextraction features are easily formed using painting or printingtechniques. FIG. 24 (b) shows a circular extraction feature 315 made ofa circle of scattering material placed on the surface of the lightguide. FIG. 25(a) shows an extraction feature 316 formed using a“halftone” or “dither” technique, in which the area of the extractionfeature is filled with smaller areas 317 of scattering material. Thesemay be made of dots or other shapes. The small areas of scatteringmaterial fill a portion of the overall area of the extraction feature,and that portion may be adjusted during fabrication by adjusting thepattern in order to change the total amount of light scattered by theextraction feature. One use of this technique is to compensate for thechanging intensity of light propagation within the lightguide along itslength, in order to maintain a more uniform output intensity along thelength of the luminaire.

FIG. 25 shows an alternative example of a dithering pattern, in which acircular extraction feature 318 is divided into wedges and a portion 319of the wedges provided with scattering material. Clocking (rotating) ordithering the pattern amongst several extraction features in a givengroup, as depicted in FIG. 25, would minimize the perception of anyhalf-toning pattern in the total output beam. Additionally, beam shapingcan be achieved through this technique to add more energy to portions ofthe angular extent of the beam.

Part 9: Lightfield Luminaire

To properly light a given space and/or objects, a specific illuminationdistribution (“lightfield”) is desired. Achieving this illuminationdistribution often requires a collection of different light fixtures andcan result in significant over-lighting as the output pattern ofstandard commercial fixtures will not perfectly match the requirementsof a given scene. Such over-lighting carries unnecessary additional costin lighting fixtures and lamps, and results in excessive energy use.This section describes a novel luminaire design that provides for facileand low-cost customization to produce desired static illuminationpatterns.

A customized lightfield luminaire is shown in cross-section in FIG. 26and perspective view in FIG. 27. It is comprised of a lightguide 520that is lit by light sources 521. The lightguide 520 is formed oftransparent plastic or glass. The lightguide 520 has extraction features522 on one surface. An array 523 of focusing dielectric-filledreflectors 524 is placed on the opposite surface of the lightguide,separated by a small air gap that provides optical cladding. Theextraction features 522 are located approximately at the focal plane ofthe reflectors 524.

The extraction features 522 are preferably formed by scattering pigmentsuch as white paint or ink and may be produced on the surface of thelightguide 520 by any number of processes including inkjet printing,silk screening, pad printing, and similar processes.

Light rays 526 from the light sources 521 are scattered by theextraction features and a portion of them emerge from the light guide tointeract with the reflectors and emerge from the luminaire as an outputbeam. Because the extraction features are located at the focal plane ofthe reflectors, rays scattering from an extraction feature at a givenlocation will be at least partially collimated and result in a beamexiting the luminaire at a particular angle. For each reflector 524there is an associated area 530 on the light guide. The pattern ofextraction features 522 may be different in each area 530. The patternof extraction features 522 in the area 530 is effectively projected bythe reflector 524 into an output beam 532.

The area 530 may be thought of as being divided into an array of smallpixels, each of which corresponds to a different output beam angle andeach of which may optionally contain an extraction feature. Pixels inthe center of the area 530 result in beams that exit perpendicular tothe plane of the light guide, while pixels offset from the center resultin beams that emerge at a corresponding angle. The total output of theluminaire is the sum of the beams produced by each reflector in thearray 523. Therefore, the total light power at any given beam angle isdependent upon the number of light guide areas 530 in which thecorresponding pixel contains an extraction feature.

An example is shown in FIG. 28 (a). An array of extraction features areplaced in an array of light guide areas 530 associated with a reflectorarray. In this simulation, a large circular center extraction feature533 is placed in half of the light guide areas, a triangular extractionfeature 534 is in the other half, and a smaller circular extractionfeature 535 is in all the light guide areas. These three extractionfeatures combine in the projected illuminance pattern, which features around central beam 536 resulting from the extraction features 533, asmaller high-intensity angled circular beam 537 resulting from theextraction features 535, and an angled triangular wash resulting fromthe extraction features 534. This illumination pattern is shown in FIG.28 (b), which is an intensity plot of beam power vs angle.

By controlling the pattern of extraction features printed on the lightguide, any arbitrary luminance pattern can be produced. Intensity ateach beam angle is controlled by varying the number of light guide areas530 in which extraction features are placed at the correspondingposition.

A second method of varying beam intensity is to print the extractionfeatures using a half-tone approach, as shown in FIGS. 24 and 25. Withina given pixel, the material of the extraction feature is printed insmall dots or other shapes dithered to set the amount of extractedlight. The dither may be applied with a randomized pattern so that it isnot visible in the total output beam, which contains the sum of thedithering projected by multiple different reflectors. Further, the pitchof the dither may be made sufficiently small that the dithering is notevident even in the projected beam from a single reflector.

There is considerable prior art on uniform planar light guide sources(for example backlight units) that describes optimization of extractionfeature density and density gradients in order to ensure uniform andhigh efficiency extraction of light from a light guide. The sameprinciples can be applied to the patterned lightguide of the customlightfield design. The pixel pattern and/or halftone in each subcell canbe adjusted to ensure that the desired extraction feature density anddensity gradients are achieved, when analyzed on a subcell-by-subcellsize scale. Optimization of the patterns may also be carried out tominimize self-shadowing of the output light by the extraction features.

A number of variations on this design are possible.

First, the reflector array 523 may be made movable rather than fixed. Inthis case, the position of the reflector array may be adjusted relativeto the light guide. Doing so will cause the orientation of the lightguide subcells and the reflectors to shift, causing the output beampattern to be steered. This provides a mechanism for a steerable outputbeam of arbitrary pattern.

Second, the reflective lens array may be irregular, containing lenses ofvaried design. Different lenses may be optimized to project beams atdifferent angles, permitting higher precision in achieving a given lightdistribution than can be achieved using a uniform lens array.

Third, it is possible to utilize a refractive lens array in place of areflective array as shown in FIG. 29. In this case, a refractive lensarray 540 is placed against the lightguide 520 with a small gap forcladding. The refractive lenses will produce a different correlationbetween extraction feature position and output beam angle, but otherwisethe design of the luminaire is very similar to the reflective arraycase. A further variation shown in FIG. 30 is to use matched arrays ofrefractive lenses 550 and reflectors 551; this is referred to as a“catadioptric” system. If properly designed, the catadioptric systemmaintains a flatter focal plane than a single optic system and thereforecan enable finer control over the illuminance pattern.

Fourth, the extraction features may be made of colored scatteringmaterial rather than white scattering material. This will cause light ofonly the specific color to be directed into the output beam. Alightguide that is patterned with extraction features in a variety ofcolors will project that colored design. This provides a facilemechanism for producing lamps that project colored scenes, images, orlogos.

Fifth, the extraction features may contain downconverting materials(such as phosphors) that change the wavelength of light as well asscatter it. A short wavelength light source can be used, with longerwavelengths produced by the downconverting material in the extractionfeatures. Further, different downconverting material compositions may beused in different areas of the patterned lightguide in order to producea variety of hues in the output pattern.

Sixth, the extraction features may be made non-planar. The extractionfeatures may be formed as volume features that protrude into thelightguide.

Seventh, the luminaire may be designed so that the patterned lightguideis removable and replaceable. This allows the illumination pattern ofthe luminaire to be changed if desired.

Eighth, the lightguide may be made of a fixed component and a removablecomponent, in order to facilitate changes to the illumination pattern.Extraction features are instead printed on a lightguide film which islaminated onto the fixed lightguide. The lightguide film may be attachedto the fixed lightguide with an optically transparent adhesive.Alternatively, the lightguide film may be formed of a “cling” materialsuch as vinyl that naturally adheres to the lightguide.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art thatchanges and modifications may be made without departing from thisinvention in its broader aspects and, therefore, the appended claims areto encompass within their scope all such changes and modifications.

What is claimed is:
 1. An apparatus for emitting light comprising: oneor more light sources; an electrical connection and heat-spreadingelement connected to the light sources; a focusing element configured tofocus light emitted from the light sources to produce a beam of lightthat is at least partially collimated; and an adjuster configured toalter, over a range of positions, an in-plane position of the focusingelement with respect to the light sources, thereby enabling control ofan overall light beam emitted by the apparatus.
 2. The apparatus ofclaim 1 wherein the focusing element comprises a refractive lens.
 3. Theapparatus of claim 2 further comprising a reflective lens disposed withrespect to the light sources and the refractive lens such that lightemitted by the light sources first strikes the reflective lens and thentransits the refractive lens.
 4. The apparatus of claim 1 wherein thefocusing element comprises a reflective lens having a receiving facethat is illuminated by the light sources to reflect light from the lightsources.
 5. The apparatus of claim 4 wherein the reflective lenscomprises a dielectric-filled reflective lens.
 6. The apparatus of claim4 wherein the electrical connection and heat-spreading element isconfigured to only partially block light reflected by the reflectivelens.
 7. The apparatus of claim 6 wherein the electrical connection andheat-spreading element comprises a narrow strip.
 8. The apparatus ofclaim 1 wherein the electrical connection and heat-spreading elementcomprises one or more metal-core printed circuit boards.
 9. Theapparatus of claim 1 wherein the light sources are one or morevertical-cavity surface emitting lasers.
 10. The apparatus of claim 1wherein the light sources are one or more light emitting diodes.
 11. Theapparatus of claim 10 wherein the light emitting diodes havesubstantially flat emission faces.
 12. The apparatus of claim 1 whereinthe one or more light sources comprise only a single light source. 13.The apparatus of claim 1 wherein the adjuster is further configured toat least laterally translate a position of the focusing element withrespect to one or more of the light sources, thereby enabling control ofa direction of the overall light beam emitted by the apparatus.
 14. Theapparatus of claim 1 wherein the adjuster is further configured to atleast adjust a distance between the focusing element and at least one ofthe light sources, thereby enabling control of divergence of the overalllight beam emitted by the apparatus.
 15. The apparatus of claim 1,wherein the adjuster is manually-operated.
 16. The apparatus of claim 1,wherein the adjuster is operated by actuators connected to a controlsystem.
 17. The apparatus of claim 1 wherein the one or more lightsources comprise multiple light sources.
 18. The apparatus of claim 1wherein the focusing element comprises a reflective lens having a lightreceiving face that is illuminated by the light sources to reflect lightfrom the light sources, and further wherein: the electrical connectionand heat-spreading element is configured to only partially block lightreflected by the face of the reflective lens, the light sources arelight emitting diodes, and the adjuster is further configured to atleast laterally translate the focusing element with respect to the lightsources, thereby enabling control of a direction of an overall lightemitted by the apparatus.